Odd tail/turn signal problem
While driving our 1998 Grand Caravan recently with the lights on in the rain a warning chime came on, as well as the right turn indicator dimly and steady. A check of the exterior lights indicated the right front parking light and lower right taillight bulb were both burning brighter than usual. The top right taillight was, or appeared to be, slightly dimmer. A check of the right turn signal showed both front and rear right signal bulbs indicating only slightly brighter than as parking/taillights alone. When the parking/driving lights are turned off, the right signal flashes as normal, but both LEFT taillight bulbs come on dimly in synch with the right signal.
Swapping around bulbs only, bulbs in sockets, even switching the entire rear light assemblies left and right, has no effect on the problem.
Brake lights work normally. The 4-way flashers appear to be working normally, except both the upper taillights come on dimly in synch with the flashers. Is this normal?
The car has a factory towing wiring harness. One day earlier we had been towing a trailer and had not noticed this as a problem. The vehicle is very new to us, so we have no idea if there it has any kind of a history of this.